Not Sweden, but the UK (and Germany) have the same thing.
Usually, they just tell you on the shelf's price tag:
Bigger Font: 1.50€/£
Smaller Font: 0.75€/p per 100g/100ml etc.
That way, you can see that sometimes it makes sense to buy 2x 400ml ketchup (just as an example where I had it recently) instead of 1x 800ml, simply because 2x 400ml is actually cheaper.
> That way, you can see that sometimes it makes sense to buy 2x 400ml ketchup (just as an example where I had it recently) instead of 1x 800ml, simply because 2x 400ml is actually cheaper.
That applies to plenty of dastardly stuff too e.g. the big 3-5kg pots of Nutella you see around Christmas? The unit price is often twice that of the standard 750g pot.
Usually, they just tell you on the shelf's price tag:
Bigger Font: 1.50€/£ Smaller Font: 0.75€/p per 100g/100ml etc.
That way, you can see that sometimes it makes sense to buy 2x 400ml ketchup (just as an example where I had it recently) instead of 1x 800ml, simply because 2x 400ml is actually cheaper.